The present invention relates to an interlock mechanism for operatively coupling a torque disconnect mechanism and a brake mechanism in a vehicle.
When servicing or diagnosing a transmission it is desirable to disconnect the transmission output shaft and prevent torque from being transmitted to the output shaft. It has been proposed to have a torque disconnect mechanism which includes a shift collar which is accessible though an opening in a transmission housing when a removable plug is removed from the opening. It would be desirable to prevent vehicle movement while an operator removes the plug to operate the torque disconnect collar.
Accordingly, an object of this invention is to provide a mechanism which prevents vehicle movement while an operator manipulates a torque disconnect mechanism.
These and other objects are achieved by the present invention, wherein a transmission includes a parking brake which is spring engaged and which is disengaged by hydraulic pressure. A torque disconnect mechanism controls transmission of torque from a first shaft to a second shaft in a transmission. The torque disconnect mechanism includes a movable shift collar inside a housing. The shift collar is accessible through an opening in the housing. A plug member is mounted in the opening and is removable to provide access to the shift collar. The housing includes a hydraulic fluid passage which communicates the park brake pressure supply line to an aperture in the opening. When the plug member is removed from the opening the aperture is opened to the environment, fluid pressure is relieved from the park brake pressure supply line and the park brake is spring applied.